Small-dimensioned coupler plug, especially for a planar broadband lambda probe

ABSTRACT

A small and compact coupler plug for a planar broadband lambda probe includes a housing having a basic body and a cover element as well as electrical components, which can be inserted into the housing and fixed in place, as well as an adjustment unit for a probe, in particular a planar broadband lambda probe, the adjustment unit being arranged within the coupler plug or outside the coupler plug via a further contact element. The cover element can be mounted over the balancing unit, and primary and secondary locking devices that cooperates with the cover element may be provided, the secondary locking device being configured as a fixing element to fix in place at least one electrical contact that is inserted in the housing, and this fixing element also having support elements that point to the cover element, such that the cover element closes in the end position of the secondary element.

FIELD OF THE INVENTION

The present invention relates to a coupler plug connector, inparticular, for a plug connector for a planar lambda probe.

BACKGROUND INFORMATION

Coupler plugs are used for the connection between a cable harness plugand a lambda probe. The terminals provided in the coupler plug are usedfor the adjustment, the signal, and/or the heating of the probe.Currently, lambda probes in combination with lambda regulation and 3-waycatalytic converters, are used for exhaust-gas purification. The lambdaprobe, which can be screwed into, for example, an exhaust gas system,includes a sensor for ascertaining the oxygen content in the exhaustgas.

The residual oxygen content is very well suited as a measuring variableand regulates the air-fuel ratio, because the latter indicates preciselywhether the air-fuel mixture is burning completely.

In this context, the lambda probe generates a voltage signal, whichrepresents the instantaneous value of the mixture composition, and whichfollows the mixture changes. The fuel supply to the engine is regulatedby a carboration system in accordance with the signal from the lambdaprobe such that a stoichiometric air-fuel ratio λ=1 is achieved. Inaccordance with the design of the exhaust gas system and with theconditions for use, heated or unheated probes are used. The lambda probehas other uses apart from motor vehicles, e.g., for regulating gasmotors or oil/gas burners.

In particular, broadband lambda probes have a modular design and, inconjunction with planar techniques, can be integrated in a plurality offunctions. They typically have functional layers, which are made up of aporous protective layer, an external electrode, a sensor foil, aninternal electrode, a reference air channel foil, an insulation layer, aheating element, a heating foil, a resistor or an adjustment element,and terminal contacts.

Because the broadband lambda probe is made up of the combination of aNernst concentration cell (sensor cell) and a pump cell that transportsoxygen ions, it is able to carry out very precise measurements not onlyin the stoichiometric point at λ=1, but also in the lean and rich range.

Every probe is individually adjusted for a balancing effect. For thispurpose, the probe has a built-in resistor (“mini-hybrid”). Theadjustment may be accomplished by ablating the resistor layer that issituated on a ceramic substrate using a laser beam, thus generating achange in the resistance and resulting in a balancing.

In a given embodiment, the adjustment unit, or the resistor, may bearranged on the probe. In an alternative exemplary embodiment, theresistor is arranged outside, for example, on a cable harness plug thatis coupled to the probe.

Heretofore, the balancing has been carried out by transporting thehousing of the coupler plug to the balancing position without the coverelement, the resistor being installed in the coupler plug. According tothis technique, after the appropriate laser treatment for the balancing,the cover element is then subsequently mounted at a different assemblyposition.

To prevent humidity, contamination, or the like from penetrating intothe coupler plug, and to assure that the appropriate atmosphere ispresent within the coupler plug, the cover element has additional seals.In addition, pressure compensating elements are arranged on the housingof the coupler plug.

One disadvantage of this design is that additional working and assemblysteps are necessary after the balancing to close up the coupler plug ina functionally correct manner.

In addition, it is necessary to separately manufacture a supplementalcover element along with a seal, and to make this cover elementavailable in the balancing area.

SUMMARY

An object of the present invention is to provide a coupler plug for aplanar broadband lambda probe that can be produced in a cost-effectivemanner and have very small dimensions.

This object may be achieved by providing a coupler plug that includes acover element that can be mounted over the adjustment element, and thathas primary and secondary locking device that cooperates with the coverelement, the secondary locking device being provided as a fixing elementto fix in place at least one electrical contact that is installed in thehousing. The fixing element also has support elements that point to thecover element, such that the cover element only completely closes in theend position of the secondary element (the fixing in place of theelectrical contact).

According to an example embodiment of the present invention, the couplerplug is configured so as to be of small dimensions, because, due to thecompact installation of electrical contacts in a basic body and thearrangement of the adjustment element likewise in the coupler plug, theexternal dimensions of the coupler plug, which may be arranged between acable harness and a lambda probe, are very small.

In addition, according to an exemplary embodiment, the coupler plugaccording to the present invention may include only a small number ofparts. As a result, a cost-effective and efficient manufacturing processcan be implemented.

Because the basic body may be completely surrounded by the coverelement, it is possible to seal off the interior of the coupler plugthrough an arrangement of sealing lips within the cover element, or anarrangement of seals in the basic body, so that the coupler plug isprotected, particularly from spray water and/or soiling.

This also aids in the latching of the cover element to the basic body.According to an embodiment of the present invention, a first and secondlatching device, or a primary and a secondary locking device, areprovided. The latter may be configured such that the cover element haslatching arms, which, in the closed state of the cover, are in contactwith the basic body of the coupler plug and bring about a coupling thereusing latching hooks.

According to a further embodiment, the primary locking device operatesin two stages. In a first stage, the cover element latches such that itis held on the basic body. As a result of continued pressure of thecover element in the direction of the basic body, the fixing elementembedded in the basic body may be fixed onto the electrical contactelement running in the basic body, for example, a planar plug sleeve,which is connected to the lambda probe. However, the fixing only takesplace by the fixing element being pressed onto the contact element, sothat the contact element and the fixing element have a secureconnection. In addition, the fixing element may be restrained in thebasic body, which means that, in the mounted state of the contactelement, the fixing element moves only in the axial push-on direction ofthe cover. In addition, support elements may be provided on the fixingelement, pointing away from the fixing element, the support elementsextending in the direction of the cover element.

In the non-actuated state of the secondary locking device, i.e., thenon-fixing of the contact element, the support elements may extend farbeyond the basic body of the coupler plug such that the cover element isheld only by the first latching action of the primary locking device. Inresponse to a complete activation and thus the proper fixing in place ofthe contact element, the cover element undergoes the second latchingaction of the primary locking device.

This has the advantage that it is possible in a simple manner to checkwhether a successful contacting and therefore securing of the electricalcontact element has been achieved with respect to the lambda probe, andthat the cover element is tightly closed with respect to the basic body.

Advantageously, hanging devices may be provided on the periphery of thecover element which make it possible to secure the coupler plug onanother part, for example, using a groove-and-tongue connection, or,alternatively, through hanging devices such that electrical lines can bemounted on the coupler plug.

Mounting possibilities are optionally provided for spray-water sleeves.

A further advantage of the present invention is that the aforementionedseals on the cover element can be injectionmolded, so that they arearranged in a nondetachable manner.

To assure a constant transition resistance between the adjustment unitand the electrical contact elements, a solder connection is provided.

The cover element is advantageously made of PBT (polybutyleneterephthalt) or equivalent materials.

In a further advantageous exemplary embodiment of the present invention,the cover element is configured so as to be transparent. As a result, itis possible that the cover element can be mounted even before thebalancing, because, if the cover elements are transparent, the balancingcan be carried out through the cover element using a laser beam.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a perspective view of the coupler plug according to thepresent invention, having a detached cover element.

FIG. 2 depicts a rear view of the coupler plug as shown in FIG. 1.

FIG. 3 depicts a top view of the coupler plug as shown FIG. 2.

FIG. 4 depicts a perspective, cut-away view of the coupler plug shown inFIG. 1, having a cover that is mounted in place.

FIG. 5 depicts a cut-away view of the cable harness plug shown in FIG. 1having the cover element in the first latching position.

FIG. 6 depicts a cut-away view of the cable harness plug shown in FIG. 1having the cover element immediately before the end position.

FIG. 7 depicts a cut-away view of the cable harness plug shown in FIG. 1having the cover element in the end position.

DETAILED DESCRIPTION

Coupler plug 1, depicted in FIGS. 1 through 4, includes a housing 2,which is composed of a basic body 3 and a cover element 4.

Arranged on basic body 3 in a retaining device 5 is an adjustment unit6, which is coupled via electrical contact elements 7 to a lambda probethat connects to the coupler plug 1 via a connecting element 8.

Electrical contact elements 7 are made of metal strips that are shapedto resemble printed circuit traces, the strips on terminating on oneside in coupling area 9 (shown in FIG. 4) of coupler plug 1.

Adjustment unit 6 is guided by guide elements 10, which are mainlyarranged on basic body 3, and it is held in position by electricalcontact elements 7.

To prevent lateral shifting of adjustment unit 6, support elements 11are provided perpendicular to the longitudinal extension of adjustmentunit 6. These support elements 11, as shown in greater detail in FIGS.5, 6, and 7, may be configured as a part of a fixing element 12.

Fixing element 12 is provided as a secondary locking element and has thefunction to hold in position an electrical contact 13, which is arrangedin housing 2, and which may be connected to the lambda probe.

For this purpose, fixing element 12 may be configured in itscross-section in a W shape, enclosing electrical contact 13 axiallybetween its two arms 12 a/12 b, in the assembled state (shown FIG. 7).

The secondary locking element, i.e., fixing element 12, may also beconfigured such that it forms a single piece along with support elements11.

In the pre-assembled state of electrical contact 13, as is depicted inFIG. 5, support elements 11 extend far out of housing 2, so that coverelement 4, which is mounted on housing 2, can be fixed only in a firstlatching.

The result is that, when the secondary locking device is not activated,the fixing of electrical contact 13 is not functional, and thepositioning of fixing element 12 is positioned such that cover element 4does not close (see FIG. 5).

With the correct end position, the cover element 4 adopts its own endposition.

The secondary locking device, once assembled, cannot be detached afterbeing locked without destroying coupler plug 1.

Advantageously, coupler plug 1 has on its circumference grooves 14,which make it possible to insert the coupler plug 1 into retainersupports provided for this purpose.

In addition, arranged in basic body 2 are retaining and fixing elements16, as depicted in FIG. 2, which make it possible to arrange couplerplug 1 on electrical lines 16, as depicted in FIG. 1.

For this purpose, retaining element 15 is configured as a clip, so thatcoupler plug 1 can be plugged into a cable phase winding when theretaining element 13 is in the open position, and the coupler plug canthen be closed as a result of a further motion.

In this way, the coupler plug can be mounted, for example, on an engine(support).

Due to its small external dimensions, it is also possible to accommodatethe coupler plug in a grooved tube.

What is claimed is:
 1. A coupler plug for a planar lambda probe,comprising: a housing including a basic body and a cover element;electrical components fixably inserted into the housing; at least onefirst electrical contact inserted in the housing; an adjustment elementmounted on the basic body, the covering element configured to cover theadjustment element, the adjustment element configured to adjust a planarbroadband lambda probe; a primary locking device; and a secondarylocking device including a fixing element for fixing the at least onefirst electrical contact, and including support elements; wherein theprimary locking device and the secondary locking device each cooperatewith the cover element, and the support elements of the secondarylocking device extend toward the cover element such that the coverelement completely closes only when the secondary locking device is inan end position.
 2. The coupler plug of claim 1, further comprising: asecond contact element, the lambda probe being arranged outside thecoupler plug and coupled to the coupler plug via the second contactelement.
 3. The coupler plug of claim 1, wherein the cover element istransparent.
 4. The coupler plug of claim 1, wherein the secondarylocking device is arranged between the basic body and the cover element.5. The coupler plug of claim 1, wherein the lambda probe is arrangedwithin the coupler plug.
 6. The coupler plug of claim 5, furthercomprising: third electrical contact elements including spring elements;wherein the adjustment element is supported on the housing by the springelements of the third electrical contact elements.
 7. The coupler plugof claim 6, wherein the third electrical contact elements areelectrically connected to the adjusment unit via soldered connections.8. The coupler plug of claim 6, wherein the electrical componentsinclude plug-in contacts.
 9. The coupler plug of claim 8, wherein thethird electrical contact elements are electrically connected to theplug-in contacts.
 10. The coupler plug of claim 9, wherein the thirdelectrical contact elements and the plug-in contacts are integrated in asingle piece.
 11. The coupler plug of claim 1, further comprising: ahanging element arranged on a periphery of the coupler plug.
 12. Thecoupler plug of claim 11, wherein the hanging element is configured agroove for engaging a tongue element.